Electrostatic propulsion means



3 1 F; v 3. 8 S 12213 3 0T1.9?05

Jan. 1, 1963 w. J. COLEMAN ETAL 3,07

ELECTROSTATIC PROPULSION MEANS Filed O ct. 6. 1958 2 Sheets-Sheet 1Lines of electrostatic force INVENTORS. w AM .co AN 0 EL es 0 ATTORNEYJan. 1, 1963 w. J. COLEMAN ETAL 3,071,705

' ELECTROSTATIC PROPULSION MEANS Filed Oct. 6. 1958 2 Sheets-Sheet 2 Jage O-- Source FIG. 4

h :3 V0743 FIG. 2

Source IN V EN TORS.

WILLIAM J.COLEMAN DANIEL F. DESANTO ATTORNEY United States Patent3,071,705 ELECTROSTATIC PROPULSION MEANS William J. Coleman, PortJelferson, and Daniel F, De

'Santo, Huntington Station, N.Y., assignors to Grum- -n1an AircraftEngineering Corporation, Eethpagc,

N.Y., a corporation of New York Filed Oct. 6, 1958, Ser. No. 765,661

12 Claims. (Cl. 313-63) This invention relates to electrostaticpropulsion means, and more particularly to means for propelling air andother fluids by electrostatic forces acting upon such fluids and forpropelling devices through air and other fluids by such forces.

It is well known that if an electrically-charged conducting surface hasa relatively sharp point, a large part of the charge will concentrate inthe neighborhood of the point, thus producing a high electrostaticstress in the air surrounding the point. Free electrons present in thisregion of air will be accelerated so strongly by the elsctrostatic forcethat by collision with neutral gas molecules they will strip or knockloose other electrons from those molecules. Thus, electron-positive ionpairs will be created and the cumulative collision process known ascorona will result. Further, if the pointed conductor is positivelycharged, the positive ions present in the corona discharge will moveaway from the point because of mutual electrostatic repulsion, while thenegative electrons will be attracted to the conductor. Neutral moleculeswill be struck by the repelled positive ions and momentum will betransferred from the ions to the air mass in the vicinity of the point,thereby generating a flow of air. This flow of air, or socalled electricwind, will be in directions radially outward from the point of thepositively charged conductor and therefore of little or no use aspropulsion means. In order to provide a useful and efficient device, theflow of air must be concentrated in one direction.

Accordingly, it is the primary object of this invention to provide inthe vicinity of the ionization point of a corona discharge device ofother ionization means, an electrostatic field whose lines of force areconcentrated along a desired flow axis originating at the ionizationpoint whereby practically all of the ions produced, along with entrainedneutral molecules, will flow in the desired direction. Further thereto,it is an object to provide in the vicinity of such ionization means, aconducting surface electrically energized and so shaped in cross-sectionas to produce an electrostatic field in the desired direction.

It is a further object to provide means downstream of the ionizationpoint to further restrict the electrostatic field to a downstreamdirection. Further thereto, it is an object to provide a conductingsurface or surfaces a variable distance downstream of the ionizationpoint to establish an end point for the lines of force emanating fromthe electrically energized conducting surface and ionization point,thereby preventing the electrostatic field from diverging while allowingsubstantially unimpeded airflow.

It is a still further object to provide downstream of the ionizationpoint, electrostatic field or fields having lines of force substantiallyparallel and in the downstream direction to confine the airflow in thedesired downstream direction.

Other objects of the invention, as Well as the advantages thereof willbecome apparent from the following description when read in conjunctionwith the accompanying drawings in which:

FIG. 1 is a cross-sectional view schematically illustrating oneembodiment of the invention;

FIG. 2 is a cross-sectional view schematically illustrating anotherembodiment of the invention;

3,071,705 Patented Jan. 1, 1963 FIG. 3 is a perspective view of stillanother embodiment; and

FIG. 4 is a cross-sectional view of the device of FIG. 3 provided withadditional means for preventing the electrostatic field from diverging.

As shown in FIG. 1, the device of the present invention comprises anionization head 10 threadedly mounted for longitudinal adjustment uponone end of a C-shaped bracket or connector 11, which in turn is fixedlyattached to a toroid 12 whose axis coincides with that of the head 10. Asuitable high voltage D.C. source 13 has one terminal connected to thetoroid 12 and another terminal connected to ground.

It is characteristic of electrostatic lines of force that theyconcentrate in those places on the surface of a conductor where theradius of curvature is the least; that they are normal to the surfacefrom which they emanate; and that such lines of force do not cross oneanother, but when influenced by such lines emanating from another body,will cause one another to bend and thereby change direction. With thisin mind, it will be noted that the crosssection of the toroid 12 is suchthat the lines of force emanating therefrom upon the application of apositive charge from the voltage source 13 would be concentrated in thedirection of the arrow A. However, because such lines of force and thoseemanating from the ionization head 10 will not cross one another, thelines of force emanating from the toroid are bent outwardly while thelines of force emanating from the ionization head 10 are bent inwardlyor compressed to thereby take a desired downstream direction as shown bythe arrows on'the ends thereof. Since the positive ions in the vicinityof the positively charged ionization head 10 are-repelled from the headand travel along the lines of force, and since momentum will betransferred from the ions to the air mass, a flow of air is generated inthe direction of the flow arrow. The air, as it moves to the right, isreplenished by an inflow of air through the toroid, thereby ensuringcontinuous operation of the device.

As previously indicated, the head 10 is mounted for longitudinaladjustment. Thus the head may be positioned with respect to the toroid12 to vary the resulting airflow and to permit the optimum placementthereof to obtain the greatest airflow possible under differentoperating conditions.

As shown in FIG. 2, means for ionizing the air comprise a heatingelement 14 positioned on the axis of the toroid 12 and supplied with anelectric current from a source 15. The high voltage D.C. source 13 isconnected to the toroid 12, which in turn is connected by means of aconductor 16 to the negative side of the source 15. The operation of thedevice shown in FIG. 2 is similar to that of the FIG. 1 device andfurther explanation is therefore deemed unnecessary.

Referring now to FIG. 3, there is shown a device which utilizes anionization head 10 and toroid 12 similar to those shown in FIG. 1, andprovided with means downstream thereof to establish an end point for thelines of force emanating from the ionization head and the toroid. Suchmeans comprise a streamline-shaped metal target 17 connected to andsupporting a metal ring 18. As shown, the positive terminal of the highvoltage source 13 is connected to the toroid 12, while the negativeterminal thereof is connected to the target 17. The target 17 and ring18 connected thereto thereby become sources of electrons whichneutralize all of the ions striking the surfaces of the target and ring.Since substantially all of the ions repelled by the head 10 will strikeeither the target 17 or the ring 18, a closed circuit is therebyestablished which permits operation of the device with no appreciablenet accumulation of charge.

The ionization head 10 is mounted upon the connector 11 for longitudinaladjustment as in FIG. 1, and is provided with a plurality of needlepoints 19 which are symmetrically spaced in rows around the head andwhich are given a positive charge from the source 13 so as to securepositive ion flow. The longitudinal adjustment of the ionization headpermits the optimum placement of the head with respect to the toroid, asindicated hereinabove with reference to FIG. 1, while additional controlmeans may comprise provision for varying the distance between the toroidand the downstream metal ring and target.

In the arrangement shown in FIG. 4, a series of metal rings 20-22, eachcharged to a DC. potential, are positioned between the toroid 12 and thedownstream ring 18. As shown, the rings 20-22 are connected throughresistors 23-26 to each other and to the toroid 12 and the ring 18. Theresistors are preferably so selected to provide a linear potentialgradient between the toroid 12 and the grounded ring 18 whereby aconstant strength electrostatic field between the toroid 12 and the ring18 is obtained. The advantage in so selecting the resistors and thusobtaining such electrostatic field is that the repelled ions will fallthrough equal potential increments between collisions with molecules,regardless of their downstream position, and each ion will thereforegain equal increments of kinetis energy between collisions. Thus, theenergy transfer from the ions to neutral molecules will be evenly spreadover the entire volume between the ionization point and the ring 18 andtarget 17. A further and possibly greater advantage is that a constantstrength electrostatic field consists of parallel electrostatic lines offorce in the downstream direction, thereby providing further means formaintaining the ion flow in the desired downstream direction.

From the foregoing, it will be apparent that the invention provideshighly effective apparatus for propelling fluid mediums such as air. Bythe ionization of molecules and the concentrating of electrostatic linesof force along and in the direction of a desired flow axis, the ions soproduced are caused to move in the desired direction. Momentum istransferred from the moving ions to the fluid mass, thus creating thedesired fluid flow.

Although shown and described in what is believed to be the mostpractical and preferred embodiments, it is apparent that departurestherefrom will suggest themselves to those skilled in the art and may bemade without departing from the spirit and scope of the invention. Wetherefore do not wish to restrict ourselves to the particular forms ofconstruction illustrated and described, but desire to avail ourselves ofall modifications that may fall within the scope of the appended claims.

Having thus described our invention, what we claim is:

1. An electrostatic propulsion device comprising means for ionizing afluid, an electrically energized conducting surface positioned relativeto said ionizing means and adapted to produce an electrostatic fieldwhose lines of force concentrate along an axis subtsantially passingthrough said ionizing means, those lines of force emanating from saidionizing means, a plurality of conducting surfaces spaced from eachother and downstream from said electrically energized conductingsurface, a connector between said electrically energized conductingsurface and that conducting surface of said plurality of conductingsurfaces nearest thereto, connectors between adjacent conductingsurfaces of said plurality of conducting surfaces, and a connection toground from that conducting surface of said plurality of conductingsurfaces most remote from said electrically energized conductingsurface, said connectors including means to provide a linear potentialgradient between said electrically energized conducting surface and saidgrounded conducting surface.

2. A device as set forth in claim 1 wherein said electrically energizedconducting surface is a toroid having its axis coincident with that ofsaid ionizing means.

3. A device as set forth in claim 1 wherein said plurality of conductingsurfaces comprise metal rings whose axes are coincident with that ofsaid ionizing means.

4. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, a toroid up stream of said point andsurrounding said means and having its axis coincident with that of saidmeans, means for electrically energizing said toroid, said toroid beingadapted to produce upon energization an electrostatic field whose linesof force concentrate about said axis and in the downstream directionthereof, those lines of force emanating from said ionizing means, aplurality of metal rings spaced from each other and downstream from saidtoroid and having their axes coincident with the axis of said toroid, aconnector between said toroid and the ring nearest thereto, connectorsbetween adjacent rings, and a connection to ground from that ring mostremote from said toroid, said connectors including means to provide alinear potential gradient between said toroid and said grounded ring.

5. A device as set forth in claim 4 and including a grounded conductingsurface positioned on the axis of and in the plane of the ring mostremote from said toroid.

6. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, and conducting surface upstream ofsaid point, a source of electric potential connected to said conductingsurface, said'conducting surface being adapted to produce anelectrostatic field whose lines of force concentrate along an axissubstantially passing through said ionizing means those lines of forceemanating from said ionizing means, target means spaced downstream fromsaid conducting surface to establish an end point for said electrostaticlines of force, and means connecting said target means to the negativeside of said source of electric potential.

7. An electrostatic propulsion device comprising means for ionizing afiuid in the vicinity of a point, a toroid upstream of said point andsurrounding said means and having its axis coincident with that of saidmeans, a source of electric potential connected to said toroid, saidtoroid being adapted to produce upon energization an electrostatic tieldwhose lines of force concentrate about said axis and in the directionthereof those lines of force emanating from said ionizing means, targetmeans spaced downstream from said toroid to establish an end point forsaid electrostatic lines of force, and means connecting said targetmeans to the negative side of said source of electric potential.

8. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, a toroid upstream of said point andsurrounding said means and having its axis coincident with that of saidmeans, means for electrically energizing said toroid, said toroidproducing upon energization an electrostatic field whose lines of forceconcentrate about said axis and in the direction thereof those lines offorce emanating from said ionizing means, a plurality of metal ringsspaced from each other and downstream from said toroid and having theiraxes coincident with the axis of said toroid, a connector between saidtoroid and the ring nearest thereto, connectors between adjacent rings,and means connecting that ring most remote from said toroid to thenegative terminal of said electrical energizing means, said connectorsincluding means to provide a potential gradient between said toroid andthat ring connected to said negative terminal.

9. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, a toroid upstream of said point andsurrounding said means and having its axis coinciding with that of saidmeans, means for electrically energizing said toroid, said toroid beingadapted to produce upon energization an electrostatic field whose linesof force concentrate about said axis and in the downstream directionthereof those lines of force emanating from said ionizing means, aplurality of metal rings spaced from each other and downstream from saidtoroid and having their axes coincident with that of said toroid, aconnector between said toroid and the ring nearest thereto, andconnectors between adjacent rings, said connectors including means toprovide a linear potential gradient between said toroid and the ringmost remote therefrom.

to. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, means positioned relative to saidionizing means for creating an electrostatic field whose lines of forceconcentrate about an axis those lines of force emanating from saidionizing means, a plurality of conducting surfaces spaced one fromanother and downstream from said ionizing means and said electrostaticfield creating means, connectors between adjacent conducting surfaces,and means for electrically energizing said conducting surfaces, saidconnectors including means to provide a linear potential gradientbetween said conducting surfaces.

1 1. An electrostatic propulsion device comprising means for ionizing afluid in the vicinity of a point, means positioned relative to saidionizing means for creating an electrostatic field whose lines of forceconcentrate about an axis those lines of force emanating from saidionizing means, a plurality of rings spaced from each other anddownstream from said ionizing means and said electrostatic fieldcreating means and having their axes coincident with that of saidionizing means, connectors between adjacent rings, and means forelectrically energizing said 5 rings, said connectors including means toprovide a'linear potential gradient between said rings when energized bysaid energizing means.

12. A device as set forth in claim 9 wherein the ring most remote fromsaid toroid is connected to ground.

References Cited in the file of this patent UNITED STATES PATENTS1,357,466 Moller Nov. 2, 1920 15 2,264,495 Wilner Dec. 2, 1941 2,460,175Hergenrother Jan. 25, 1949 2,636,664 Hertzler April 28, 1953 2,658,009Ransburg Nov. 3, 1953 2,765,975 Lindenblad Oct. 9, 1956 20 2,809,314Herb Oct. 8, 1957.

FOREIGN PATENTS 262,829 Great Britain Feb. 16, 1928

1. AN ELECTROSTATIC PROPULSION DEVICE COMPRISING MEANS FOR IONIZING AFLUID, AN ELECTRICALLY ENERGIZED CONDUCTING SURFACE POSITIONED RELATIVETO SAID IONIZING MEANS AND ADAPTED TO PRODUCE AN ELECTROSTATIC FIELDWHOSE LINES OF FORCE CONCENTRATE ALONG AN AXIS SUBSTANTIALLY PASSINGTHROUGH SAID IONIZING MEANS, THOSE LINES OF FORCE EMANATING FROM SAIDIONIZING MEANS, A PLURALITY OF CONDUCTING SURFACES SPACED FROM EACHOTHER AND DOWNSTREAM FROM SAID ELECTRICALLY ENERGIZED CONDUCTINGSURFACE, A CONNECTOR BETWEEN SAID ELECTRICALLY ENERGIZED CONDCTINGSURFACE AND